Transcript shampoos
SHAMPOOS INTRODUCTION The word 'cosmetics' arises from a Greek word 'kosmeticos' which means to adorn. Since that time any material used for beautification or improvement of appearance is known as “cosmetic” The cosmetics in general are external preparations and are meant to be applied to external parts of the body. In other words they may be applied to skin, hair and nails for the purposes of covering, colouring, softening, cleansing, nourishing, waving, setting, preservation, removal and protection. All cosmetics are formulated as solids, semi-solids or liquids. SHAMPOOS • A good shampoo should almost immediately form abundant foam irrespective of the type of water used to clean the hair • The functions of the shampoos are 1. It completely and effectively removes the dust, sebum and residual substances 2. It must effectively wash the hair 3. It should produce a good amount of foam 4. It must easily clear on water wash 5. It should leaves the hair non dry and softness 6. It should impart pleasant fragrance to the hair 7. It should not cause irritation to skin and eye COMPOSITION OF SHAMPOOS • Surfactants are the main component of shampoos. Mainly anionic surfactants are used. cationic, non-ionic and ampholytic surfactants have also used • The raw materials used in manufacture of shampoos are classified as: 1. Principal surfactants which provide detergency and foam. 2. Secondary surfactants which improve detergency foam and hair condition. 3. Other additives which impart other characteristics to the shampoo products. PRINCIPAL SURFACTANTS • Anionic surfactants are mostly used as principal surfactant. They have very good foaming properties. • Non-ionic surfactants have good cleansing activity but do not have sufficient foaming power. • Cationic surfactants have good foaming character as well as some cleansing power but are not much used as they are toxic and cause damage to the eye. • Ampholytic surfactants are generally not as good as anionic. Also they are more expensive. So, they are mainly used as secondary surfactants and as good hair conditioners PRINCIPAL SURFACTANTS Alkyl sulphates: Alkyl sulphates are most widely used anionic detergents, particularly lauryl and myristyl sulphate various salts of lauryl sulphates like sodium lauryl sulphate, triethanol lauryl sulphate, monoethanol lauryl sulphate and ammonium lauryl sulphate are used. Triethanolamine alkyl sulphate is present in most of the present day shampoos Alkyl polyethylene glycol sulphates: Sulphate derivatives of lauryl alcohol ether with polyethylene glycol are good cleansers. Normally a chain of 2-3 ethylene oxide molecules is condensed. Sodium salts of these alkyl ether sulphates are more water soluble than sodium lauryl sulphate and thus a concentrated, product can be made. Addition of sequestering agents like salts of EDTA or poly phosphates is required for stabilization SECONDARY SURFACTANTS • These are added to produce more foam and to improve the condition of the hair. • They are mostly anionic or ampholytic detergents. • Monoalkyl sulphosuccinates are non-irritant to the eyes and thus may used in body shampoos. • Dialkyl derivatives like sodium di (ethyl hexyl) sulphosuccinate and the di (tertiary) nonyl sulphosuccinate are very good wetting agents and are used for wetting and penetration action. • Methyl taurides, amides of methyl taurine, are amphoteric. They leave the hair in excellent condition because of the presence of the amide group. • Monoethanolamides and isopropanolamides, are used along with lauryl sulphate to increase the solubility and thus to increase lather. OTHER ADDITIVES (a) Germicides and anti-dandruff agents (b) Conditioning agents (c) Pearlscent agents (d) Sequestrants (e) Thickening agents (f) Colors (g) Perfumes (h) Preservatives GERMICIDES AND ANTI-DANDRUFF AGENTS Germicides and/or antidandruff agents are incorporated to prevent microbial infection of scalp and to treat dandruff respectively. Common germicides are quaternary ammonium compounds, benzalkonium chloride, cetrimide and phenol derivatives; tetramethyl thiuram disulphide. Substances used as anti-dandruff agents are selenium sulphide, cadmium sulphide, zincundecylenate, sodium sulphacetamide etc. CONDITIONING AGENTS Conditioning agents are mainly fatty substances like lanolin, oils; natural products like herbal extracts, egg, amino acids, lecithin and polymeric substances. These substances give a special conditioning effect to the hair. If amino acids are incorporated into shampoos, after washing amino acid remains deposited on the hair and scalp and produces a good conditioning effect on the hair. Protein hydrolysates containing amino acids are incorporated for conditioning effect. PEARLSCENT AGENTS • Pearlscent agents are also used to give special conditioning to hair. They brighten the hair. • For this purpose 4 -methyl coumarins are used in 0.2l% concentration and they act better at pH between 4.5-6. • Fluorescence materials are also occasionally used. SEQUESTRANTS • They form a water soluble complex with Ca++ and Mg++ and thus prevent the formation of insoluble salts of soaps or detergents by these two divalent ions present in water. • Sometimes calcium salt dispersing agents are incorporated to disperse the salts formed by the divalents Ca++, Mg++ etc. • Sequestrants like sodium salt of EDTA are used to entrap the Ca++ and Mg++ present in the water THICKENING AGENTS • To make shampoo preparations viscous, for thickening and minimize wastage while pouring, thickening agents are incorporated. • The substances normally used for this purpose are alginates, polyvinyl alcohol, methyl cellulose, colloidal silicates, polyethylene glycols. • Some times a suitable combination of surfactants also make the preparation viscous. Sulphated castor oil along with sulphated olive oil is one such combination. COLOURING AGENTS: • Colours are preferred by several people and thus suitable certified colours can be incorporated to produce a visually attractive impact. The colours should be water soluble. • Perfumes: Perfumes are also incorporated to have an after-use fragrance on hair. They also help to mask the odour of the other ingredients particularly detergent various perfumes are used for this purpose. Perfumes are used in 0.3-1.0%. PRESERVATIVES • Preservatives are very important as most products are liable to attack by microbes. • This leads to breakdown of the product, odour, discoloration and cloudiness. • Water-soluble preservatives are to be used and phydroxy benzoic acid and its methyl ester, phenyl mercuric compounds and formaldehyde may be used. PREPARATION OF SHAMPOOS • They are prepared by simple mixing process. In powder shampoos the ingredients are simply mixed and the perfume is added last. • In case of clear liquid shampoos the detergents are first dissolved in half of the water with little heat if necessary. • Other ingredients are added to other part of the water and then mixed with the first part. Then perfume is added last. LIQUID CREAM SHAMPOOS • Such shampoos are expected to be mild and emollient in action. Non-ionic stearates like propylene glycol stearate, polyethylene glycol 400 distearate together with insoluble metallic stearates are used for opacification. SOLID CREAM/GEL SHAMPOOS • These are made from sodium lauryl sulphate paste with suitable gelling agent such as sodium stearate. Since they have to be stored in collapsible tubes or jars, they should have thick consistency. OIL SHAMPOOS • Oil shampoos basically consist of detergents made of sulphonated oils. They have good cleansing ability to remove dirt and oil from the hair but they do not form foam. • Sulphonated vegetable oils are made by treating vegetable oils with sulphuric acid or other sulphonating agents, and are good detergents. EVALUATION OF SHAMPOOS Shampoos are before releasing to the market, must be tested for their safety or application to the skin and eyes. General tests for identification of ingradients and quantity of each ingredient should be carried out by proper chemical analysis. Some other specific tests are done. 1. Various physical properties These are foam formation and foam stability, rheology of the products, nature of foam, effect of the shampoo on the hair and its characteristics. Effect on the hair can be studied by half-head technique, where half of the hair is shampooed, the other half is used as control, and comparing the two parts by observation. 2. Effect on skin and eyes This can be done by applying it on animals. Irritation on skin can be studied by applying it on skin and observing the effects on skin.